Internal-combustion engine



Aug. 19 1924. 1,505,211

J. LORBACH INTERNAL COMBUSTION ENGINE Filed Jan- 6. 192] 3 Sheets-Sheet 1 Hill INVENTOR Aug. 19 1924. 1,505,211

J. LORBACH INTERNAL COMBUSTION ENGINE Filed Jan- 1921 3 Shoots-Sheet 2 (F, e I as v VI 18 n i 3 17 ,l 22 M "21 6\ I 1 21 1 1 1 a :3. 15 s n 7 I" i I I i a V 2 M A a 9 I, a; I /////1 !NVENTOR Patented Aug. 19, 1924.

lTED STATES J'OSEF LORBACH, OF BERLIN-FRIEDENAU, GERMANY.

INTERNAL-COMBUSTION ENGINE.

Application filed January 6, 1921.

Serial No. 435,504.

(GRANTED UNDERIHE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L, 1313.)

To all whom it may concern:

Be it known that I, J OSEF LORBACH, a citizen of the German Empire, residing at Berlin-Friedenau, Germany, have invented certain new and useful Improvements in Internal-Combustion Engines (for which I have filed applications in Germany, September 17, 1917, Patent No. 309,7 81, and April 8, 1918, Patent No. 317,272; England, July 8, 1920, July 9, 1920; Sweden, June 29, 1920; Italy, July 9, 1920; France, July 30, 1920; Norway, June 30, 1920; Poland, July 4/7, 1920; Czechoslovakia, July 9, 1920; -Belgium, July 10, 1920), of which the following is a specification.

My invention refers to internal combustion engines and more especially to valveless two-cylinder engines working on the two stroke cycle principle. It is an object of my invention to provide an engine distinguished over others by the complete expulsion of the gases of combustion by scavenging after each working stroke, combined with a very economical consumption of scavenging air, the fresh charge being supplied distinctly separate from the scavenging air, and the latter being fed in centrally, while the sparking plug is being cleaned by a current of air blowing over it before each fresh sparking action. All these advantages combine to achieve a high-degree of both thermal and volumetric efficiency and great reliability in working.

I obtain all these advantages simultaneously by utilizing the piston for distributing purposes in a three-fold manner, inasmuch as on the one hand the piston connects the air pump with the surrounding atmosphere, whilst on the other hand governing the connection between the carburettor and the charging pump and furthermore controlling the central inlet port for the scavenging air and the mixture. In my "improved engine the sparking plug is arranged vertically above the injecting nozzle which is located in the centre of the piston.

In order to obtain a particularly short piston and, consequently, small reciprocatingmasses, thereby ensuring a particularly high number of revolutions and at the same time very materially reducing the overall 2, on the left).

height of the engine, I prefer arranging the working piston so as to slide on a stationary hollow body, the piston body being fitted with openings of such width as to allow of the air required for a full charge passing through with each stroke. Moreover the openings of these passages are arranged in that part of the piston which permanently remains above the hollow body. With the piston in its lowest position, these openings are therefore located below the stepped portion of the cylinder, while still remaining above the hollow body.

In the drawings aflixed to this specification and forming part thereof, two modifications of an internal combustion en 'ne embodying my invention are illustratef by way of example. In the drawings- Figs. 1 and 2 are longitudinal sections of the simpler modification illustrating two different positions of the pistons, while Figs. 3 and 4 are longitudinal sections of the preferred form, the two diflerent positions of the pistons illustrated being the same as in Figs. 1 and 2.

Figs. 5 and 6- are cross-sections on the lines V-V in Fig. 3 and VIVI in Fig. 4, respectively.

Referring to Figs. 1 and 2 of the drawings, the lower part of the body 1 of each of the pistons a is fitted with an annular flange 2. That part of the piston which is situated above this flange, slides in the narrower part 3 of the cylinder 1) which isstepped at 5, the flange 2 on the other hand sliding in the wider portion 4 of the cylinder. Space I above the piston head 6, constitutes the working chamber, space H above flange 2 the air-pump space and space III below flange 2 is the charging-pump space. Thebody of the piston is provided with a number of slots 7 distributed over the periphery of the piston, these slots attaining a position below the step 5 in the cylinder on the piston reaching its lowest position (Fig. These slots communicate with the crank case 8 by way of the interior of the piston, and thence with the surroundiIIg atmosphere through an opening 9 located in the crank case wall.

- The tail end of the piston is surrounded by an inwardly projecting flange 11 of the wider portion of the cylinder 4 and is provided with indentures 1O establishing a connection around flange 11 between space III and the mixture supply pipe coming from the carburettor, when the piston has reached its highest position (Fig. 2 on the right).

The air-pump space II of each cylinder communicates with an annular groove 14: in the other cylinder by means of intermediate pipes 13 and 13 which cross one an other. On the other hand the chargingpump space III of each cylinder communicates with an annular groove 16 of the same cylinder by means of a by-pass 15. In both cylinders the annular groove 16 is arranged directly beneath the annular groove 14. Corresponding to these annular grooves'in the two cylinders each of the pistons is provided around the periphery near the top with an annular row of slots 17, all of which lead toa common nozzle 18 arranged in the centre of the piston head 6 and pointing upwards. The sparking plug 19 is fitted on top of and coaxially with the blast nozzle and the cylinder. The upper end of the cylinder has the shape of a closed vaulted hood 20. In consequence of this configuration a current of air striking the hood is caused to spread in umbrella shape and is deflected evenly on all sides, as indicated by the arrows on the left in Figs. 1 and 2.

A third annular groove 21 is provided in each cylinder just above the annular r groove 14, said groove 21 forming the connection with the exhaust piping 22.

The operation of the engine above described is the following:

During the downward stroke of the piston on the left in Fig. 1 a partial vacuum is produced in space II of the left hand cylinder, whilst the upward stroke of the right hand piston which takes place simultaneously, likewise causes a vacuum to be generated in the space III of the right hand cylinder. Towards the end of the stroke the slots 7 in the left hand piston are uncovered, thus allowing air from the surrounding atmosphere to flow into the crank chamber 8 through the opening 9 and thence through the interior of the piston into space II on the left until this latter is filled with air of atmospheric pressure. In passing through the crank chamber this air is mixed with some atomized oil, thus causing a satisfactory lubrication of the sliding surfaces of the piston upon coming into contact with the latter. Simultaneously with the opening of the slots 7 of the left hand piston the indentures 10 of the right hand piston have connected space III of the right hand cylinder with the carburettor. the right hand space III thus being filled with mixture of atmospheric pressure.

During the subsequent upward stroke of the left hand piston and downward stroke of the right hand piston (Fig. 2). the air containedin space II on the left. and the mixture in space III on the rightare copressed.

Compression of the air is carried on as long as the pipe 13 which opens into the right hand annular groove 14, is shut 03 by the right hand piston. Accordingly the mixture in the right hand cylinder also continues to be compressed until the right hand piston uncovers the right hand annular groove 16. The annular groove 14 is the first to be uncovered owing to the slots 17 in the piston reaching it.

As regards the left hand cylinder the compressed air contained in the right hand space II passes through the intermediate pipe 13 and into the annular groove 16 on the left (Fig. 2), whence it reaches the working chamber 1 through the slots 17 in the piston and the nozzle 18. On arriving in space I it drives the burnt gases contained in the space before it, blows the soot and oil deposits off the sparking plug. and is deflected in umbrella shape by the bowl-shaped inner surface of the hood forming the end of the cylinder, thus finally ejecting a large portion of the burnt gases from space I, the space hitherto occupied by the burnt gases now being filled with air. In the meantime the slots 17 of the piston will have reached the annular groove 14, thereby establishing a connection between space III on the left and the nozzle 18 through the by-pass 15 and allowing the compressed charging mixture to reach the working space I on the left. With this arrangement the remainder of the burnt gases and possibly also a small proportion of the scavenging air are discharged through the annular groove 21 into the ex haust pipe 22, while the charging mixture 1s kept away from the annular groove 21 by a broad intervening layer of air. Finally the working chamber I contains nothing but charging mixture and combustion air. the charging mixture chiefly ocupying the central part of this space. i. e. that part where the air and the mixture had moved upwards, whilst the combustion air settles along the walls of the cylinder and encloses the mixture contained in the centre.

During the next upward stroke of the left hand piston the mixture is compressed in a well known manner, together with the air, the mixture and the combustion air being mixed sufficiently by this compression. Ignition takes place at the end of the stroke and is followed by the working stroke, whereafter the process described is repeated with both pistons and cylinders interchanged.

In the second modification of this engine the upper part 23 of the crank casing is equipped with hollow upright head-pieces 24 which serve for conveying the charging mixture. These upright head-pieces should preferably be separate units in order to allow of using different materials for the crank casing proper and its head-piece, and moreover in order to render exchanging of the head-piece possible. The bearing 25 of the connecting rod in the piston is arranged high up in the piston and near the piston head and the ports 7 which are provided in the piston body for letting in the air, are also located near the upper end of the piston. As compared with the modification described in the first place the whole of the piston body below the annular extension 2 has been dispensed with in this case, whilst on the'other hand a piston packing 26 has been added inside at the annular extension.

The upright head-piece 24 is connected to the mixture supply piping 12 and contains distributing ports '27 which are accommodated in hollow extensions 29 of the upright head-piece 24 arranged on both sides of the connecting rod 28. The exterior surfaces of these extensions 29 are shaped cylindrically and are utilized for guiding the inner surface of a piston a on each of them. At the top, near 30, these guide surfaces also contain the end openings of the ports 27 It will be observed in Fig. 4 that it is essential for the step 5 in the wall of the cylinder to be situated above the slots 7 in the piston, when the piston a has reached its lowest position, whilst the upper end of the hollow body 29 must remain below the slots 7 of the piston.

The mode of action of this second modification is exactly like that described above with regard to the first one. However the second modification involves a shorter and lighter piston and consequently a smaller overall height of the whole engine.

Machining the upright head-piece 24 can be simplified and cheapened by dividing it into two pieces shaped absolutely alike by means of a joint in IVIV. The channels 12 for conveying the charging mixture are then sealed by plugs 31, each half of each plug engaging with one of the parts of the upright head-piece 24 which guide the pis ton (Fig. 6). The plugs may consist of some elastic material such as india-rubber inasmuch as they are only subject to small differences of pressure and are not exposed to particular rises in temperature.

I claim 1. A two-stroke cycle internal combustion engine, comprising in combination, two c linders having air and fuel ports therem, flanged difl'erential area pistons adapted to compress air for scaven ing and combustion,

cross-connections where y the air compression space of each cylinder is connected to the combustion chamber of the other cylinder, means whereby the flange of each piston operates to pump fuel into the combusthe fuel are injected into the combustion chamber when said ducts register with the respective ports of the cylinder.

2. A two-stroke cycle internal combustion engine, comprising in combination, two cyllinders having air and fuel ports therein, flanged differential area pistons adapted to compress air for scavenging and combustion, cross-connections whereby the air compression space of each cylinder is connected to the combustion chamber of the other cylinder, means whereby the flange of each piston operates to pump fuel into the combustion chamber of the cylinder appertaining tosaid piston, and a nozzle on each piston, communicating by means of duets with the sides of the piston, whereby the air and the fuel are injected into the combustion chamber when said ducts register with the respective ports of the cylinder, domed heads on said cylinders and spark plugs disposed centrally in said heads above said nozzles.

3. A two-stroke cycle internal combustion engine, comprising in combination, two cylinders having air and fuel ports therein, flanged differential area pistons adapted to compress air for scavenging and combustion, cross-connections whereby the air compression space of each cylinder is connected to the combustion chamber of the other cylinder, means whereby the flange of each piston operates to pump fuel into the combustion chamber of the cylinder appertaining to said piston, and a nozzleon each piston, communicating by means of ducts with the sides of the piston, whereby the air and the fuel are injected into the combustion chamber when said ducts register with the respective ports of .the cylinder, slots being provided in the piston sleeves above the flanges for admitting air from the crank case to the. air compression chamber.

4. A two-stroke cycle internal combustion engine, comprising in combination, two stepped cylinders having air and fuel ports therein, flanged differential area pistons with air slots adapted to compress air for scavenging and combustion, a stationary hollow body extending into each piston underneath the air slots, the steps of the cylinders being above said air slots in the lowest position of said pistons, cross connections whereby the air compression space of each cylinder is connected to the combustion chamber of the other cylinder,.

- crates to pump fuel into the combustion spective ports of the cylinder, slots being chamber of the cylinder appertaining to provided in the piston sleeves above the said piston, and a nozzle on each plston, flanges for admitting air from the crank 1 communicating by means of ducts with the case to the air compression chamber.

sides of the piston, whereby the air and the In testimony whereof I afiix my signafuel are injected into the combustion chamture. ber when said ducts register with the re- JOSEF LORBACH. 

